Antioxidant activity of macromolecular compounds of humic etiology

Dependance of antioxidant activity of the humic macromolecular compounds from their etiology and production method was learned by means of physical-chemical analysis methods - colorimetry with diphenylpicrylhydrazyl (DPPH) as a stable radical, cathodic voltammetry, electron paramagnetic resonance spectroscopy. 18 native humic acids (HAs) were isolated by extraction from nine typical species of peats of the Tomsk region, that differ from each other by botanical composition, degree of decomposition and ash content. Two extragents were used: sodium hydroxide and sodium pyrophosphate. Although all 18 HAs samples exhibit antioxidant activity. At the same time there is a similar trend in the distribution of antioxidant activity, which is proved by Spearman's correlation analysis. A higher activity was noted for pyrophosphate HAs. Using methods of cathodic voltammetry and colorimetry with DPPH it was found that HAs show antioxidant activity by its mechanism, being a proton donor due to the presence of a large number of phenolic hydroxyls. EPR spectroscopy established that the HAs are traps of free radicals.